WASHINGTON
- Pilots have flown through the prohibited airspace protecting the White
House at least 94 times over the past decade, illustrating the challenges
of thwarting a terrorist airstrike on the nation's capital.

Even with
military jets patrolling the skies, four commercial airliners and a
medical helicopter have crossed into Washington's no-fly zone since
the Sept. 11 suicide hijackings, Federal Aviation Administration officials
said.

An uproar
over a jet that flew over the White House this week prompted disclosures
that numerous planes have failed to follow procedures when operating
near the nation's capital.

New security
requirements imposed in the weeks after Sept. 11 require planes flying
into Reagan National, located just across the Potomac River from U.S.
landmarks, to properly identify themselves to air traffic controllers
before landing. If they fail to do so, then they are diverted.

The Frontier
Boeing 737 that failed to veer away from restricted air space over the
White House immediately after taking off from Reagan National for Denver
had earlier in the day been diverted to Dulles when the same crew failed
to follow proper identification procedures on its way into Washington.

No fighter
jets were sent to escort the plane and it later landed in Denver without
incident. The pilot has been grounded with pay.

In most
cases, pilots who violated the airspace protecting the White House,
vice presidential mansion and Capitol have gotten penalties less severe
than a parking ticket, an Associated Press review of FAA enforcement
records found.

Just a
month before the September hijackings, a Mesa Airlines flight strayed
into prohibited airspace. By November, the matter was closed with a
warning letter to the pilot — common for most cases.

Security
experts say violations of the Washington airspace highlight a key reality
in the fight against terrorism — planes that veer into the zone can
crash into government installations within seconds.

"Practically
speaking, by the time a violation is discovered, it is too late to do
anything to prevent a crash into the White House," former FAA security
chief Billie H. Vincent said.

FAA Deputy
Administrator Monte R. Belger said Thursday the agency recognizes there's
little time to react once planes penetrate the safety zone and so the
government has imposed numerous other precautions to ensure planes with
ill intent don't get close.

"The
restricted area is kind of the last line of defense," Belger said.
"The additional on-the-ground security procedures and in-flight
protocols put in place give us a much higher level of confidence."

Borders
have been tightened; pilots, flight crews and passengers are screened
to weed out possible terrorists, and planes approaching Washington must
complete authentication procedures, including providing passwords.

About three
dozen planes approaching Reagan National Airport have been turned away
since Sept. 11 because they didn't complete the verification process,
officials said.

Planes
that violate the prohibited zone are quickly warned by the flight tower
to correct course, and the Secret Service is alerted. Nearly all pilots
comply immediately, officials said.

Military
planes that patrol the capital skies are permitted to force such planes
to land or, as a last resort, shoot them down if pilots don't respond.

In an announcement
last fall about improved protection of Washington's airspace, the FAA
said pilots who infringed the no-fly zone faced "suspension or
revocation of their licenses or a fine."

But FAA's
enforcement database, obtained by AP under the Freedom of Information
Act, shows nearly all the violators since 1992 have gotten just a warning
letter.

Of the
111 pilots on the 94 flights, just one was fined, for $1,000, and nine
had their licenses suspended for between seven to 120 days.

At least
90 cases were settled by administrative action, mostly warning or correction
letters, the records show. Four violating pilots had their penalties
reversed later.

One pilot
died when he crashed his small plane into the White House in the mid-1990s;
no one else was harmed. In 1999, a pilot drifted so close to the White
House that agents fired a warning flare. That pilot ended up with a
warning letter, FAA records say.

White House
national security officials opposed reopening Reagan National after
the Sept. 11 hijack attacks, fearing its close proximity to the White
House, Pentagon and the U.S. Capitol complex posed a serious security
risk.

One of
the planes hijacked by terrorists took off from Dulles and was flown
into the Pentagon.

But the
Bush administration relented to political and public pressure and allowed
the airport to reopen almost a month after the attacks. Service has
been allowed to resume gradually and Reagan National now operates at
75 percent capacity. That is equivalent to roughly 600 takeoffs and
landings each day.

"Air
security is certainly something we deal with on a daily basis, both
with being in constant communication with tower at Reagan and with the
FAA," Secret Service spokesman James Mackin said.

One pilot
caught in the airspace blamed air traffic controllers, saying they are
so busy they sometimes order flight maneuvers that send pilots into
the prohibited zone.

"The
D.C. controllers are absolutely horrible. Washington National is absolutely
the worst place to fly into, period," said Happy Wells, a 30-year
veteran pilot from Oklahoma who was cited in July 1997 for flying his
charter plane through Washington's prohibited zone.

Wells said
his proposed penalty was rescinded after he filed a report with the
FAA.

The air
traffic controllers union defended the work of their Washington employees.
"Pilots have consistently reinforced the opinion that National
has some of the best controllers in the air traffic control system,"
spokesman Doug Church said.

Operators
of Reagan National said the violations aren't necessarily a sign of
lax security. Pilots can be knocked off course by something as simple
as heavy wind.

FAA says
it has settled most cases with warning letters because it believes pilots
were operating in good faith at an airport considered one of the toughest
to navigate.

A
passenger jet has violated airspace restrictions above the White House,
flying as low as 300 metres (1,000 feet) over the home of the US president.

The two pilots of Frontier Airlines flight 819 have been suspended after
reportedly acknowledging errors that took the plane through the most
restricted airspace in the United States.

The
plane failed to make a steep turn after take-off and flew almost directly
over the White House, where President George W Bush was at the time.

There
have always been security precautions for government buildings in Washington,
but these were tightened after the 11 September attack on the Pentagon
- and fighter jets continue to patrol the skies.

The
Frontier Boeing 737 plane took off from Reagan National Airport - just
across the Potomac River from the Washington landmarks - at 1815 local
time (2345 GMT) heading for Denver, Colorado.

A
spokeswoman for the US Federal Aviation Administration said the plane's
pilot was contacted by air traffic controllers and acknowledged making
an error.

Laura
Brown said: "The pilot missed the first turning point.

"He
did manage to go through part of the restricted airspace."

She
said the plane was monitored by "appropriate security agencies".

Pentagon
attacks

A
spokeswoman for the Denver-based airline, Tracey Kelly, said the pilots
had been grounded by the carrier until federal and company investigations
were completed.

"We're
working with the FAA and the TSA [Transportation Security Administration]
to determine what happened and make sure it does not happen again,"
Ms Kelly said.

Before
the 11 September attacks on the Pentagon and New York, flights departing
Reagan National Airport followed the Potomac River, bringing planes
close to CIA headquarters, the White House, the Capitol and the Pentagon.

White
House security officials were reluctant to reopen the airport after
the attacks and allowed flights to resume only gradually.

WASHINGTON
(CNN) -- A Frontier Airlines jet flew into restricted airspace near
the White House as it took off Monday evening from Ronald Reagan Washington
National Airport, according to the Federal Aviation Administration.

Frontier
Flight 819, a Boeing 737-300, took off to the north from the Reagan
airport and -- instead of turning to the left as required -- continued
straight and into restricted airspace, said FAA spokesman Bill Shumann.

The
jet was just inside restricted airspace, he said, within two miles of
the White House.

Shumann
said the FAA will investigate and considers the matter a case of possible
"pilot deviation," which the agency defines as "an action
of a pilot that violates any federal aviation regulation."

The
spokesman said there could be disciplinary action against the pilot
in the form of a reprimand or license revocation.

Frontier
Airlines is a low-cost airline based in Denver, Colorado.

According
to the FAA, this marks the fourth time since September 11 that a commercial
aircraft has flown into prohibited airspace over Washington:

On
December 22, a commercial aircraft strayed into the restricted airspace.

On
January 4, an American Airlines flight taking off from Reagan National
made an error similar to that of the Frontier aircraft, continuing straight
instead of turning.

On
March 8, a U.S. Airways aircraft landing at Reagan National Airport
didn't comply promptly with instructions from air traffic controllers
and entered the off-limits airspace at 9,000 feet.

On
March 21, a Medivac helicopter departing Children's Hospital flew for
unknown reasons through the northern edge of prohibited airspace.

The
agency said in January that pilots -- 95 percent of them in small planes
-- have flown into restricted or prohibited airspace at least 270 times
since the terror attacks.

The
incidents include 10 times when pilots flew over President Bush's Crawford,
Texas, ranch and 45 times when pilots flew close to the presidential
retreat at Camp David, Maryland.

Other
planes flew too close to cities, outdoor sporting events and nuclear
power plants, the FAA said.

Violations
of the prohibited airspace over Washington were a headache for aviation
safety officials even before the terrorist attacks.

There
were 13 violations in 1996, 27 in 1997, 43 in 1998, 16 in 1999, 25 in
2000 and 26 in the first three quarters of 2001.

The
number of incursions dropped in 1999 after the FAA launched an education
campaign and issued new warnings to pilots.

In
recent years, roughly one-quarter of those flying into the off-limits
airspace over Washington were commercial air carriers. The remainder
of violators were small, general aviation aircraft.